U.S. patent application number 16/263626 was filed with the patent office on 2020-08-06 for hydraulic delta robot control system.
This patent application is currently assigned to Caterpillar Inc.. The applicant listed for this patent is Caterpillar Inc.. Invention is credited to Zhijun CAI, Corey L. GORMAN, Daniel J. MARTINEZ, Rustin G. METZGER, Eric A. REINERS, Daniel P. SERGISON.
Application Number | 20200246967 16/263626 |
Document ID | / |
Family ID | 1000003923255 |
Filed Date | 2020-08-06 |
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United States Patent
Application |
20200246967 |
Kind Code |
A1 |
CAI; Zhijun ; et
al. |
August 6, 2020 |
HYDRAULIC DELTA ROBOT CONTROL SYSTEM
Abstract
A construction system includes an excavator having a
hydraulically controlled linkage and a hydraulic robot. The
hydraulic robot includes a plurality of arms extending from a base,
each arm having a hydraulic motor. The hydraulic robot further
includes a robot control system directing movement of the plurality
of arms and an end effector platform movable by rotation of the
arms.
Inventors: |
CAI; Zhijun; (Dunlap,
IL) ; SERGISON; Daniel P.; (East Peoria, IL) ;
MARTINEZ; Daniel J.; (Peoria, IL) ; GORMAN; Corey
L.; (Peoria, IL) ; METZGER; Rustin G.;
(Congerville, IL) ; REINERS; Eric A.; (Washington,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Caterpillar Inc. |
Deerfield |
IL |
US |
|
|
Assignee: |
Caterpillar Inc.
Deerfield
IL
|
Family ID: |
1000003923255 |
Appl. No.: |
16/263626 |
Filed: |
January 31, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B25J 9/14 20130101; B25J
11/005 20130101; E02F 3/437 20130101; B25J 9/0051 20130101; E02F
9/2025 20130101; B25J 15/0028 20130101 |
International
Class: |
B25J 9/14 20060101
B25J009/14; B25J 11/00 20060101 B25J011/00; B25J 15/00 20060101
B25J015/00; B25J 9/00 20060101 B25J009/00; E02F 9/20 20060101
E02F009/20; E02F 3/43 20060101 E02F003/43 |
Claims
1. A construction system, comprising an excavator having a
hydraulically controlled linkage; and a hydraulic robot comprising:
a plurality of arms extending from a base, each arm having a
hydraulic motor; a robot control system directing movement of the
plurality of arms; and an end effector platform movable by rotation
of the arms.
2. The automated construction system of claim 1, wherein each
hydraulic motor is connected to a single valve manifold.
3. The automated construction system of claim 2, wherein the
hydraulic motor includes an encoder configured to provide position
feedback.
4. The automated construction system of claim 2, wherein the
hydraulic motor includes an encoder configured to measure an angle
of an arm relative to the base.
5. The automated construction system of claim 1, wherein the robot
control system comprises a valve manifold with a plurality of
variable solenoids.
6. The automated construction system of claim 1, wherein the valve
manifold is positioned on the base.
7. The paving system of claim 6, wherein the plurality of variable
solenoids are comprised of multiple pairs of solenoids, and each
pair of solenoids controls a pressure valve and a hydraulic motor
of an arm of the plurality of arms extending from the base.
8. The automated construction system of claim 6, wherein each
hydraulic motor on each of the arms has one or more ports, each
port connected to a solenoid of the valve manifold.
9. The automated construction system of claim 6, wherein each
solenoid is associated with a pressure sensor that provides control
feedback to the hydraulic actuator.
10. The automated construction system of claim 1, wherein the end
effector platform is configured to attach to an additive
construction nozzle, clamps, pincers, vacuum tool(s), grippers,
nail gun, screw gun, torque gun, welder, rebar tying mechanism,
brick laying mechanism, or a combination thereof.
11. A system for controlling a hydraulic robot, comprising: a
hydraulically controlled linkage of an excavator coupled to a
robot, wherein the robot comprises an end effector platform movable
by a robot arm, the robot arm having a hydraulic motor; and a
controller configured to activate the hydraulic motor by providing
a computed amount of pressure to the pressure valve.
12. The system of claim 11, wherein activation of the hydraulic
motor rotates the robot arm.
13. The system of claim 11, wherein the controller is configured
for: receiving a desired speed or desired acceleration for an end
effector platform connected to the arm; and computing the amount of
pressure based on the desired speed or the desired
acceleration.
14. The system of claim 13, wherein the controller is configured
for: computing a rotation speed and acceleration for the arm based
on the desired speed or the desired acceleration; and computing the
amount of pressure based on the rotation speed and acceleration for
the arm.
15. The system of claim 13, wherein the controller is configured
for: receiving position information for the arm; and computing the
amount of pressure based on the position information.
16. A method of controlling a hydraulic robot, comprising receiving
a desired speed or desired acceleration for an end effector
platform of a delta robot, the end effector platform connected to
multiple arms of the robot, each arm having a hydraulic motor; for
each arm of the robot, calculating arm rotation speed and arm
rotation acceleration, based on the desired speed or desired
acceleration; for each arm of the robot, calculating a change in
pressure to a respective hydraulic motor of the arm to actuate the
arm at the calculated arm rotation speed and arm rotation
acceleration; and activating a respective hydraulic motor of each
arm to rotate the arm, wherein the end effector platform is
configured to move with the rotation of each arm of the hydraulic
robot.
17. The method of claim 16, further comprising: activating a
hydraulic motor associated with an arm of the hydraulic robot,
wherein motion of the arm is based on activation of the hydraulic
motor.
18. The method of claim 16, further comprising: receiving position
information for each arm; and recalculating arm rotation speed and
arm rotation acceleration based on the received position
information.
19. The method of claim 18, wherein the multiple arms of the robot
are connected to a single base, and the position information
includes an angle of each arm relative to the base.
20. The method of claim 19, further comprising: activating the
respective hydraulic motor of each arm by sending a current to a
solenoid controlling a pressure valve associated with the
respective hydraulic motor.
Description
TECHNICAL FIELD
[0001] The present disclosure relates generally to delta robots.
More particularly, the present disclosure relates to a hydraulic
control system of such robots.
BACKGROUND
[0002] A delta robot, also known as a spider robot or parallel
robot, generally includes three arms connected at one end to a
stationary base, and at a second end to an end effector. The arms
are coupled to the end effector as parallelograms to restrict the
movement of the end effector to pure translation--movement in only
the X, Y or Z directions. The base of the robot may include three
electric motors for moving the arms to position the end effector.
Existing delta robots are commonly actuated using electrical
motors. The electric motors provide a low payload that is often
less than one kilogram. The payload limitations mean that delta
robots are used in refined manufacturing settings, where the end
effector carries only loads that do not exceed one kilogram.
Further, the electrical motors require electrical power
connections, cooling components, heavy wiring, protection from
physical overload, etc. Such requirements in electrical connections
limit delta robots to stationary or manufacturing factory
settings.
[0003] European Patent No. 2799190B1 (the '190 patent), filed by
Perl et al. on Apr. 16, 2014, describes one such delta robot with a
drive system for movement of the end effector. The drive system of
the '190 includes three actuators for moving the arms of the delta
robot. While the '190 patent broadly describes actuators as
possibly being electric, pneumatic, or hydraulic drives, the '190
patent does not describe implementation of the hydraulic drive on a
delta robot. In particular, the '190 patent does not detail how to
operate a delta robot on a mobile industrial machine, or describe
detailed control of the hydraulic drive of the delta robot.
[0004] The system of the present disclosure may solve one or more
of the problems set forth above and/or other problems in the art.
The scope of the current disclosure, however, is defined by the
attached claims, and not by the ability to solve any specific
problem.
SUMMARY
[0005] In one aspect, a construction system may include an
excavator having a hydraulically controlled linkage and a hydraulic
robot. The hydraulic robot may include a plurality of arms
extending from a base, each arm having a hydraulic motor. The
hydraulic robot may further include a robot control system
directing movement of the plurality of arms and an end effector
platform movable by rotation of the arms.
[0006] In another aspect, a system for controlling a hydraulic
robot may include a hydraulically controlled linkage of an
excavator coupled to a robot, wherein the robot comprises an end
effector platform movable by a robot arm, the robot arm having a
hydraulic motor and a controller configured to activate the
hydraulic motor by providing a computed amount of pressure to the
pressure valve.
[0007] In a further aspect, a method of controlling a hydraulic
robot may include receiving a desired speed or desired acceleration
for an end effector platform of a delta robot, where the end
effector platform may be connected to multiple arms of the robot,
each arm having a hydraulic motor. The method may also include
calculating, for each arm of the robot, arm rotation speed and arm
rotation acceleration, based on the desired speed or desired
acceleration. The method may further include calculating, for each
arm of the robot, calculating a change in pressure to a respective
hydraulic motor of the arm to actuate the arm at the calculated arm
rotation speed and arm rotation acceleration. The method may then
entail activating a respective hydraulic motor of each arm to
rotate the arm, wherein the end effector platform is configured to
move with the rotation of each arm of the hydraulic robot.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is an illustration of an exemplary machine with an
attached delta robot, according to aspects of this disclosure.
[0009] FIG. 2 is an illustration of the exemplary delta robot of
FIG. 1.
[0010] FIG. 3 is a block diagram of an exemplary control system for
controlling the exemplary delta robot of FIG. 1.
[0011] FIGS. 4A and 4B provide flowcharts depicting an exemplary
method for controlling the delta robot of FIG. 1.
DETAILED DESCRIPTION
[0012] Both the foregoing general description and the following
detailed description are exemplary and explanatory only and are not
restrictive of the features, as claimed. As used herein, the terms
"comprises," "comprising," "having," including," or other
variations thereof, are intended to cover a non-exclusive inclusion
such that a process, method, article, or apparatus that comprises a
list of elements does not include only those elements, but may
include other elements not expressly listed or inherent to such a
process, method, article, or apparatus.
[0013] In this disclosure, relative terms, such as, for example,
"about," substantially," "generally," and "approximately" are used
to indicate a possible variation of .+-.10% in the stated value.
Although the current disclosure is described with reference to a
mobile industrial machine, such as an excavator, this is only
exemplary. In general, the current disclosure can be applied to any
mobile or stationary machine, such as, for example, any excavator,
backhoe, tractor, etc. While the current disclosure references
exemplary placements of sensors, such sensors may be placed in
other suitable locations consistent with the present
disclosure.
[0014] FIG. 1 depicts an exemplary a construction system comprising
hydraulic excavator machine 10. Machine 10 may include a front
portion 12 and a rear portion 14. Front portion 12 may include a
boom 16, a stick 18, and a connecting assembly 20 for connecting an
end effector assembly 26 including a delta robot 22 and tool or
implement 23. Tool or implement 23 may include any end-effectors
for construction applications. For example, tool or implement 23
may include a nozzle for additive construction or printing.
Alternately or in addition, tool or implement 23 may include
clamps, pincers, vacuum tool(s), grippers for moving objects, nail
gun, screw gun, torque gun, welder, rebar tying mechanism, brick
laying mechanism, etc. Connecting assembly 20 coupling end effector
assembly 26 to the stick 18 may include any conventional
quick-coupling mechanism, or other connecting system known in the
art. Further, delta robot 22 may attach to a construction machine's
existing hydraulic system with a quick-couple hose system and
minimal controls wiring (not shown).
[0015] Delta robot 22 may include a base 24, arm assemblies 27, and
an end effector platform 36. The base 24 may couple to connecting
assembly 20, and the arm assemblies 27 may be rotationally
connected to the base 24. Robot 22 may include three arm assemblies
27 as shown. Each arm assembly 27 may include an upper arm 28 and a
lower arm 30. The lower arms 30 may be shaped as parallelograms. A
universal joint 32, such as a ball and socket joint, may connect
each upper arm 28 and lower arm 30. The upper arm 28, joint 32, and
lower arm 30 may be configured to maintain the orientation end
effector platform 36 (e.g., minimize tilting). The arm assemblies
27 may join to the end effector platform 36 also using universal
joints 34, such as a ball and socket joints. End effector platform
36 may be movable by rotation of the arm assemblies 27. In
particular, rotation of each upper arm 28 relative to base 24 may
cause movement of the end effector platform 36. Each lower arm 30
may transfer rotation of a respective upper arm 28 to translate the
end effector platform 36. The lower arms 30 may maintain the
position of the end effector platform 36 such that the end effector
platform 36 remains substantively parallel to the base 24 as it
moves. End effector platform 36 may be coupled to any tool or
implement 23 usable by machine 10.
[0016] Rear portion 14 of machine 10 may include an operator cab
25. Operator cab 25 may include a user interface to connect or
communicate with a control system 100 (FIG. 2) of robot 22. The
elements and layout of machine 10 are merely exemplary. As noted
above, the principles of the present disclosure may be applied to
any type of machine.
[0017] FIG. 2 depicts the exemplary robot 22 and control assembly
100. Each upper arm 28 may be equipped with a hydraulic actuator
(e.g., hydraulic motor 150) and a pressure valve 170). Control
assembly 100 may be disposed adjacent to base 24, on a frame 200.
Control assembly 100 may include a valve manifold 110 receiving
commands from a controller 360 (shown schematically). The valve
manifold 110 may be fluidly connected to a pressurized fluid source
(not shown) and a drain (not shown). Valve manifold 110 may include
a plurality of solenoids 115. Valve manifold 110 may feed and drain
one or more of the solenoids 115, based on commands from the
controller. In other words, the controller may command movement of
robot 22 using valve manifold 110 to actuate hydraulic motors 150
(supply or drain pressurized fluid). The hydraulic motors 150 may
include or entail hydraulic actuators. The controller is described
in more detail at FIGS. 3, 4A, and 4B. Each solenoid 115 may be
associated with a pressure sensor providing control feedback. For
example, each solenoid 115 may have a pressure sensor disposed on
its surface. The pressure sensor may provide a feedback loop for
controller commands.
[0018] In one embodiment, valve manifold 110 may include two
variable solenoids 115 for each hydraulic motor 150. For example as
shown in FIG. 2, robot 22 may use two solenoids 115 (e.g., solenoid
115a and solenoid 115b) to control each hydraulic motor 150. The
six solenoids 115 of FIG. 2 may be connected to hydraulic motors
150 (two solenoids per motor). In one embodiment, valve manifold
110 may additionally include spare solenoids.
[0019] The hydraulic motor 150 may be comprised of a linear-rotary
actuator such that motion of the hydraulic motor 150 may translate
into rotary motion of upper arm 28. For example, hydraulic motor
150 may include a shaft (not shown) that extends into a bore (not
shown) of upper arm 28 to engage upper arm 28. For instance, the
hydraulic motor 150 may include a splined shaft and upper arm 28
may include a cavity receiving the splined shaft. The engagement
between hydraulic motor 150 and upper arm 28 may be such that liner
motion of the hydraulic motor 150 causes rotational movement of
upper arm 28.
[0020] In one embodiment, each hydraulic motor 150 may include two
ports: an inlet port and an outlet port. A supply hose (not shown)
may connect an end of a solenoid 115a to an inlet port of a
hydraulic motor 150. A return hose (not shown) may connect an end
of a second solenoid 115b to an outlet port of hydraulic motor 150.
Each pair of variable solenoids 115 may comprise one supply
solenoid and one return solenoid. Solenoid 115a (and a supply hose)
may be used in conjunction with solenoid 115b (and a return hose).
The supply hose may supply pressurized fluid to hydraulic motor 150
to activate hydraulic motor 150. Pressurized fluid may drain from
the return hose. As previously discussed, activation of hydraulic
motor 150 may rotate upper arm 28 and cause horizontal or vertical
movement of the end effector platform 36.
[0021] The hydraulic motor 150 may include a sensor 152 disposed on
the motor 150. The sensor 152 may comprise an encoder configured to
provide position feedback of the position of upper arm 28. Position
feedback of upper arm 28 may include the position of upper arm 28
relative to base 24. In particular, sensor 152 may act as an
encoder configured to measure an angle of upper arm 28 relative to
base 24.
[0022] In one embodiment, each arm assembly 27 may include pressure
valve 170. Actuation of hydraulic motor 150 may be initiated by a
difference in pressure across pressure valve 170. A difference in
pressure across pressure valve 170, may cause the shaft of
hydraulic motor 150 to move. The robot 22 may provide fast response
to commands from the hydraulic controller, due to the close
proximity of the valve to hydraulic actuators (including hydraulic
motor 150). This is in sharp contrast to controls located at a
hydraulic pump (e.g., positioned at the rear portion 14 of machine
10, or possibly along a boom 16 or stick 18), which require time
for the fluid flow to reach the hydraulic actuators and prompt
movement. For the pressure-based embodiment, pressure may be
maintained across the pressure valve to hold an arm assembly 27
stationary, and incremental pressure may be supplied for the
pressure difference to initiate movement of the arm assembly 27. A
higher pressure difference may translate into faster motion or
rotation of the upper arm 28, while a lower pressure difference may
reduce rotational speed of the arm 28. The pressure-based hydraulic
activation mechanism provides a fast, responsive way to activate
the hydraulic motor 150, thus minimizing delays associated with
electrical motor-activated delta robot actuation. The embodiment
may also include an accumulator at each pressure valve 170, to
further speed up actuation. The accumulator may maintain a supply
of fluid so that there is no wait time for a fluid to travel down
hydraulic lines from a hydraulic pump situated at the rear portion
14 of machine 10. In other words, the illustrated embodiment of
FIGS. 1 and 2 may enhance the responsiveness of robot 22 by
positioning the pressure valve 170 adjacent to hydraulic motor 150,
maintaining steady pressure levels at end(s) of the pressure valve
170, and accumulator usage. Frame 200 may protect the arm
assemblies 27 and end effector platform 36 from contact with the
ground when delta robot 22 is detached from machine 10 or at
rest.
[0023] FIG. 3 depicts an exemplary hydraulic control system 300 for
machine 10 and robot 22. Control system 300 may include machine
controller 320, machine-to-robot control system 340, delta robot
controller 360, and delta robot actuator 380. Machine controller
320 may control machine 10 and machine-to-robot control system 340
may coordinate movement of a component of machine 10 (e.g., stick
18) and robot 22. Delta robot controller 360 may translate desired
linear motion into rotational motion to apply to robot 22, and
delta robot actuator 380 may apply differential pressure to rotate
an arm to move the platform at a desired velocity, along a desired
path.
[0024] Machine controller 320 and machine-to-robot control system
340 may each embody a single microprocessor or multiple
microprocessors that may include systems for monitoring operations
of machine 10, issuing instructions to components of machine 10,
and/or communicating with external devices. For example, machine
controller 320 and/or machine-to-robot control system 340 may
include a memory, a secondary storage device, a clock, and a
processor, such as a central processing unit or any other means for
accomplishing a task consistent with the present disclosure. The
memory or secondary storage device may store data and/or software
routines that may assist machine controller 320 and/or
machine-to-robot control system 340 in performing its functions.
Further, the memory or storage device may also store data received
from various inputs associated with work machine 10. Numerous
commercially available microprocessors can be configured to perform
the functions of machine controller 320 and machine-to-robot
control system 340. It should be appreciated that machine
controller 320 and machine-to-robot control system 340 could
readily embody a general machine controller capable of controlling
numerous other machine functions. Various other known circuits may
be associated with machine controller 320, including
signal-conditioning circuitry, communication circuitry, hydraulic
or other actuation circuitry, and other appropriate circuitry.
[0025] Robot controller 360 may embody a single microprocessor or
multiple microprocessors that may include systems for monitoring
operations of robot 22, issuing instructions to components of robot
22 (e.g., arm assemblies 27), and/or communicating with external
devices (e.g., machine 10). Robot controller 360 may receive a
desired end effector path and desired end effector velocity from
machine controller 320 and machine-to-robot control system 340. The
path and velocity may depend on the size of machine 10, as well as
the tool 23 attached to end effector platform 36. The desired path
and desired velocity may be received in Cartesian coordinates.
Robot controller 360 may convert the received path and velocity to
rotational speed. The rotational speed may be the speed of each
robot arm assembly 27, which may achieve the path and velocity of
the robot end effector platform 36. Robot controller 360 may
further compute a pressure difference to rotate arm assemblies 27
at the rotational speed. For example, robot controller 360 may send
a current to a pair of solenoids 115 corresponding to a valve and
hydraulic motor 150 of an arm assembly 27, and hydraulic motor 150
may cause arm assembly 27 to rotate at a rotational speed based on
the pressure difference provided by the solenoids 115. Alternately
or in addition, robot controller 360 may compute a pressure
difference and corresponding current to convey rotational
acceleration to arm assemblies 27.
[0026] Robot controller 360 may further operate a feedback loop, in
which the rotational speed may be adjusted based on sensor input
370 related to each robot arm assembly 27. Sensor input 370 may
include position information comprising data on an angle of each
arm assembly 27 relative to a portion of base 24. Position
information may be provided by sensor 152 positioned on the motor
150 or each arm assembly 27. Robot controller 360 may receive
information from inputs including actual machine component position
(e.g., position of stick 18), actual end effector platform
position, actual arm position and/or arm angle, desired end
effector position, desired end effector platform position, desired
end effector path, desired end effector velocity, or a combination
thereof. Robot controller 360 may output a pressure difference to
provide to each pressure valve of each arm, to move each arm at the
desired rotational speed (and/or acceleration) to achieve desired
end effector path and velocity. The pressure difference provided to
each arm assembly 27 may vary for each arm, depending on the
desired movement or position of the end effector platform 36.
[0027] Robot controller 360 may further include a memory, a
secondary storage device, a clock, and a processor, such as a
central processing unit or any other means for accomplishing a task
consistent with the present disclosure. The memory or secondary
storage device associated with robot controller 360 may store data
and/or software routines that may assist robot controller 360 in
performing its functions. Further, the memory or storage device
associated with robot controller 360 may also store data received
from various inputs associated with robot 22. Numerous commercially
available microprocessors can be configured to perform the
functions of robot controller 360. It should be appreciated that
robot controller 360 could readily embody a general machine
controller capable of controlling numerous other machine functions.
Various other known circuits may be associated with robot
controller 360, including signal-conditioning circuitry,
communication circuitry, hydraulic or other actuation circuitry,
and other appropriate circuitry.
[0028] FIGS. 4A and 4B provide further detail on exemplary
processes related to the functions and operations of machine
controller 320, machine-to-robot control system 340, delta robot
controller 360, and delta robot actuator 380.
[0029] FIGS. 4A and 4B depict an exemplary methods for operating
machine 10 in conjunction with robot 22. In particular, FIG. 4A
provides method 400 for determining a desired end effector platform
path and a desired velocity for movement of the end effector
platform. FIG. 4B provides method 420 for actuating robot 22 to
place the end effector on the desired path, at the desired
velocity. For example, method 420 includes computing a desired
rotational velocity at which to rotate arms of robot 22. Method 420
may further include calculating a pressure difference to provide to
each of hydraulic motor 150, to rotate each respective arm at the
desired and computed rotational velocity. The steps shown in FIGS.
4A and 4B described below are merely exemplary. One or more of the
steps may be omitted and/or one or more steps may be added pursuant
to the present disclosure.
[0030] Method 400 may be performed by a hydraulic control system of
machine 10. The control system of machine 10 may include a machine
control system (e.g., machine controller 320) and a
machine-to-robot coordinator control system (e.g., machine-to-robot
control system 340). While FIG. 4A depicts machine-to-robot control
system 340 performing a portion of method 400 and machine-to-robot
control system 340 performing another portion of method 400, any
step of method 400 may be performed by any control system of
machine 10.
[0031] In step 401, machine-to-robot control system 340 may
determine a desired end effector path and desired end effector
velocity. The desired velocity may include a velocity requisite to
move machine components at front portion 12 to follow a desired
path. The desired path and/or the desired velocity may be provided
by a human operator, a sensor mechanism, an automated path and
velocity calculation module, or a combination thereof. The machine
components may include boom 16 and stick 18, or any movable
components of machine 10 (e.g., a swing). Step 403 may include
prompting machine 10 move the machine components to follow the
desired path, at the desired speed.
[0032] Machine-to-robot control system 340 may calculate end
effector acceleration for the end effector to reach the desired
path at the desired velocity. For example, step 405 may include
machine-to-robot control system 340 determining a difference (e.g.,
an error) between the actual tool tip position against the desired
position, or the difference between actual tool tip velocity versus
desired velocity. The actual tool tip position and/or the actual
tool tip velocity may be provided by one or more sensors, IMU,
LIDAR, a camera, or a combination thereof. Alternately, the
difference between the actual tool tip position and the desired
tool tip position (and/or between the actual tool tip velocity and
the desired tool tip velocity) may be determined by sensor(s),
inertial measurement unit(s) (IMU), LIDAR, camera(s), or a
combination thereof. Step 407 may include calculating end effector
velocity and acceleration to compensate for the difference or the
error.
[0033] As shown in FIG. 4B, method 420 describes a process of
actuating robot 22. In one embodiment, steps 421-429 may be
performed by robot controller 360. Steps 421-437 may detail
mechanisms that take place as a results of steps 421-429. Step 421
may include receiving a desired speed and a desired acceleration
for an tool or implement 23 fastened to an end effector. The tool
or implement 23 may include any end-effector(s) for construction
applications that may be coupled to the end effector platform of
root 22. For example, the tool or implement 23 may include an
additive construction nozzle (coupled to the end effector platform
of robot 22), clamps, pincers, vacuum tool(s), grippers, nail gun,
screw gun, torque gun, welder, rebar tying mechanism, brick laying
mechanism, or a combination thereof. The desired speed and the
desired acceleration may be received from the machine controller
320 and/or the machine-to-robot control system 340. Step 423 may
include calculating rotation speed and rotation acceleration for
each arm assembly 27 of robot 22, to achieve the desired end
effector speed and desired end effector acceleration. The
calculation of step 423 may account for position (e.g., arm angle)
information received from sensor(s) positioned on each arm assembly
27. Step 427 may include computing, for each arm assembly 27, a
change in pressure (e.g., delta pressure) from the motor 150 on the
arm assembly 27, based on the calculated rotation speed and
calculated rotation acceleration for the arm assembly 27. The
calculations of step 423 and 427 take into account the interaction
of the plurality of arms of robot 22, and the movement of each arm
to translate the end effector platform 36 horizontally or
vertically with no tilting or rotation of the end effector platform
26.
[0034] Step 429 may include sending a current to each pair of
solenoids 115 corresponding to each motor 150, based on the delta
pressure computed for the motor 150. The current causes a
difference in pressure that may actuate robot 22. For example, the
pressure difference may cause the pressure valve 170 of each arm
assembly 27 to move (step 431), which may prompt each corresponding
hydraulic motor 150 to activate (step 433). Movement of each
hydraulic motor 150 may rotate the robot arm assembly 27 engaging
each motor 150 (step 435). Rotation of the assemblies 27 may move
end effector platform 36 (step 437). Movement of the end effector
platform 36 may move the end effector at the desired path and
desired velocity provided by machine controller 320.
Machine-to-robot control system 340 may monitor the movement of the
end effector and adjust commands to the robot controller 360 to
reduce discrepancies between desired and actual path/velocity of
the end effector.
[0035] The disclosed systems and methods are merely exemplary. The
methods and structures may be altered to accommodate different
operations or qualities of machine 10 and robot 22.
INDUSTRIAL APPLICABILITY
[0036] Existing delta robots are often actuated with electrical
motors which limit the payload and setting in which delta robots
are used. The disclosed aspects of a delta robot controlled by a
hydraulic motor may provide for delta robots with, among other
things: (1) a high payload capability, (2) the ability to leverage
existing hydraulic systems in construction machines and vehicles,
and/or (3) highly responsive movement. The high payload capacity
provided by a hydraulic motor may allow the delta robot to move
tools or implements that an electrically driven delta robot may not
be able to carry. In particular, the hydraulic motor may provide
the disclosed delta robot with the ability to carry and move heavy
tools or implements, such as implements what well exceed a weight
of 1 kg. Such added capacity allows the fine-tuned movement and
agility of delta robots to be applied to construction systems and
settings. Furthermore, the disclosed hydraulic motor may directly
be connected to or integrated with the existing hydraulic actuation
system of a mobile vehicle, e.g., an excavator. No separate power
line, cooling mechanism, physical overload protection, or
conversion of engine power, is needed. The disclosed delta robot 22
may simply attach to a construction machine's existing hydraulic
system with a quick-couple hose system and light controls wiring.
Lastly, the use of pressure valves with hydraulic motors may
provide for responsive movement desired in such robot systems.
[0037] In addition, while hydraulic drives are broadly known, a
desire exists for details in operating a delta robot using a
hydraulic system. Because existing delta robots are electrically
driven, delta robot control systems are commonly activated by
electrical current, rather than pressure or fluid. The disclosed
aspects of control system 300 provides an embodiment of an
implementation of controlling and actuating a hydraulic delta
robot. First, the current disclosure provides exemplary detail of
interactions between a (construction) machine controller, a
machine-to-robot control system, a delta robot controller, and a
delta robot actuator. Next, aspects of the disclosed control system
300 detail the computation of pressure or fluid needs to enact the
desired motion of the delta robot.
[0038] It will be apparent to those skilled in the art that various
modifications and variations can be made to the disclosed system
without departing from the scope of the disclosure. Other
embodiments of the system will be apparent to those skilled in the
art from consideration of the specification and practice of the
machine disclosed herein. It is intended that the specification and
examples be considered as exemplary only, with a true scope of the
disclosure being indicated by the following claims and their
equivalents.
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